Film reader

ABSTRACT

The film reader has a substantially cubic housing one wall of which is formed with a projection screen, an intake slot for a film to be projected, a focus control knob and two slots for position control levers movable along mutually normal axes near the screen. The transmission means between a film holder and respective control levers include a longitudinal carriage movable on two guiding tracks along one axis and supporting a transverse carriage for a transverse movement along the other axis. Each lever is pivotable about a fixed pivot point in mutually normal planes and is provided with an equalizing lever cooperating with a pin and slot guide. One control lever has an equalizing elbow lever hinged to a transmission lever extending transversely to the control lever and coupled to one side of the longitudinal carriage. The other control lever is coupled to the transverse carriage which supports the film by means of a closed loop Bowden wire.

BACKGROUND OF THE INVENTION

This invention relates generally to a film reader and, moreparticularly, it relates to a film reader which has a projector enclosedin a housing to project at least a portion of a film on the screen, anda film holder which is supported on a slide carriage which in turn issupported on a transverse slide carriage for movement in theillumination plane of the projector. l

In conventional film readers of this type the operator directlydisplaces the film holder in two directions in order to place thedesired film portion to be projected in front of the objective in thefilm reader. Such direct actuation of the film holder, however, has thedisadvantage that a fine position adjustment of the film is difficultespecially in the case when the film is a microfilm, the projectedportions of which are very small and require a considerablemagnification. Another disadvantage of the known film readers having aprojector located laterally to the screen is in the fact that the filmhas to be shifted in an opposite direction than that which is desired onthe screen. This condition has the consequence that in practice evenexperienced operators frequently make errors in the correct positioningof the projected image resulting in time losses.

SUMMARY OF THE INVENTION

It is therefore a general object of the present invention to overcomethe aforementioned disadvantages.

More particularly it is an object of the invention to provide animproved film reader of the aforedescribed type which enables asensitive position adjustment and selection of the projected image whilemoving the projected image on the screen in the same sense as is movedthe corresponding control member.

In keeping with these objects, and others which will become apparenthereafter, one feature of the invention resides in a film reader havinga film holder which is supported on a transverse sliding carriage whichin turn is supported for a longitudinal movement on an elongatedcarriage, in the provision of two control levers extending respectivelythrough the film reader, one of the levers being movable in onedirection and the other lever being movable in transverse direction, andtransmission means linked between the control levers and the film holderto move in a converted way, the film holder in the illuminating plane ofthe projector along two mutually normal axes. By virtue of theconversion of the movement of the control levers via the transmissionmeans, the path of movement of the end of each control lever is extendedrelative to the movement of respective carriages of the film holder. Asa result even extremely small portions of the projected film can beadjusted accurately on the screen in the desired position. The extensionof the path of movement of respective control levers of the film readeralso enables a resetting operation by providing a series of indexingmarks can be applied along each slot in the film reader housing throughwhich a control lever projects. The transmission means of this inventionfurther enables a very sensitive control and prevent an override of thefilm relative to the objective of the projector, caused by theunavoidable jerk upon overcoming the static friction at the beginning ofthe operation.

Each control lever is, at its other end inside the reader housingpivotably supported on a fixed pivot pin by which it is also guided inan oblong slot extending in its longitudinal direction. The transmissionmeans further includes an equalizing lever pivotably connected betweenthe housing and the assigned control lever to convert the circularmovement of the free end of the control lever into a substantiallyrectilinear movement along the wall of the housing. At the same time thecontrol lever performs translational movement along its guiding slot andin this manner the control knob keeps a substantially uniform clearancefrom the wall of the housing.

In the preferred embodiment the control lever for the horizontaldisplacemnt of the projected image is coupled via the transmission meansto the elongated carriage of the film holder and is swingable in a planeperpendicular to the illumination plane of the projector. In thispreferred embodiment the equalizing lever is in the form of an angularlever the apex of which is hinged to the film reader housing, one arm ofwhich is linked to the horizontal control lever and the other arm beinghinged to a transmission lever. The transmission lever is pivotablysupported for movement in the plane of the horizontal control lever andis linked to the longitudinal carriage of the film holder. The pivotpins linking one end of the transport lever to the housing and the otherend of the lever to the longitudinal slide carriage of the film holderalso cooperate, respectively, with guiding slots which enable thelongitudinal displacement of the transport lever. This pin-slot guidingarrangement enables in a very simple manner a uniform transmission ratioand the reversal of direction of movement between the control lever andthe film holder. If, for instance, the horizontal control lever isdisplaced in the direction towards the film holder, the latter is movingaway from the screen toward the interior of the housing. In this mannerit is attained a unidirectional movement of the control lever and of theprojected image.

The equalization of movement due to the slot-pin guiding means has theadvantage in the provision of a uniform transmission ratio over theentire range of movement of the horizontal control lever, the linkingtransmission lever and of the longitudinal carriage for supporting thefilm holder. This transmission assembly is mechanically very simple andis composed of a few parts only. As a consequence, it is inexpensive inmanufacture and has a negligible play in its hinge joints.

In a further elaboration of this invention, the longitudinal carriage ofthe film holder is guided in two parallel tracks each being providedwith a gear rack, the longitudinal carriage extending between the twotracks and supporting for rotation a driving shaft which in turn isprovided at its ends with driving pinions engaging the tracks and thefree end of the transmission lever being hinged to the longitudinalcarriage in the range of one of the guiding tracks.

This guiding arrangement has the advantage that the longitudinalcarriage is driven by means of a single transmission lever only coupledthereto in the proximity of one of the guiding tracks without any dangerof tipping inasmuch as all movements transmitted by the transmissionlever to one side of the longitudinal carriage are positivelytransferred by the driving shaft to the other side of the carriage sothat the latter is accurately driven in the direction of its guidingtracks.

The transverse carriage directly supporting the film holder is coupledvia the transmission means to another control lever for verticaladjustment starting from the level of the horizontal control lever neara wall which is opposite to the wall supporting the film holder. Thefilm holder is preferably accessible from the same wall which supportsthe screen. The advantage of this arrangement in which all controlelements as well as the screen and film gate are located on the samewall of the film reader housing is in the fact that the latter can besupported on any of its sides thus facilitating the adjustment of themost convenient operational position at various working situations.

The transmission means for the transverse sliding carriage includes twoBowden wires connected between the vertical control lever and thetransverse sliding carriage to effect the vertical movement of theprojected image during its horizontal displacement. In addition, theBowden wire transmission provides a problem-free motion reversal betweenthe transverse carriage and the vertical control lever so that thetransverse carriage moves in counterdirection to the movement of thevertical control lever. As a result when the control lever is moved forexample downwardly, the projected image on the screen is also movingdownwardly. The combination of a four bar linkage for the horizontaltransfer of the movement and of the Bowden wire for the verticaltransverse movement insures that the combined movement of the filmholder in both axial directions takes place independently in bothdirections without any interference.

The equalizing lever assigned to the vertical control lever isdimensioned such that the Bowden wires move on a straight line over amajor portion of the range of movement of the vertical control lever. Inthis manner it is achieved that a negligible backlash and an accurateproportionality between the displacement of the vertical control leverand the sliding movement of the film holder take place.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing:

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a front view of the film reader of this invention;

FIG. 2 shows in a bottom view the linkage between a horizontal controllever and a film holder in the reader of this invention;

FIG. 3 is a side view of a film holder in connection with its horizontaland vertical guiding means;

FIG. 4 is a linkage for transmitting the movement of a vertical controllever to the film holder;

FIG. 5 is an exploded view of vertical and horizontal control levers andof its transmission devices and

FIG. 6 is a sectional view of vertical guiding means taken along theline VI--VI in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The film reader illustrated in FIG. 1 has a substantially cubicalhousing 1 defining on one of its sides a square screen 2 mounted in afront frame 3. A slide-in film capsule 5, as seen on the right hand sideof FIG. 1, is insertable into a vertical slot 4 communicating with avertically and horizontally movable film holder 24. The film capsule 5containing the film to be projected is carried by the film holderarranged in an illumination plane of a lateral projector. Theillumination plane is in register with the slot 4 and the projectedimage is reflected onto the front screen 2 by conventional means.

A focus control knob 6 is located on the front side of the housing 1between screen 2 and the slot 4.

As seen in FIG. 1, a horizontal control lever 7 projects from ahorizontal slot 8 in the front frame 3 below the screen 2. The slot 8extends almost over the entire width of the screen 2. A second controllever 9 for adjusting the vertical position of the film projects from avertical slot 10 formed in the side of the front frame 3 opposite to thevertical slot 4 for the film capsule 5. Also the slot 10 for thevertical control lever 9 extends almost over the entire height of thescreen 2. Along respective slots 8 and 10 in the front frame 3 arearranged reference characters and numerals to facilitate the resettingof each projected image from the film.

From FIG. 1 it is apparent that all control element necessary for theoperation of the film reader of this invention are located on the frontside of the apparatus and consequently the film reader can be operatednot only in the position as shown in FIG. 1, but it can be placed on allremaining side surfaces and on the rear surface.

The film transport along one coordinate axis, in the given example alongthe axis corresponding to the movement of the horizontal control lever7, is effected by means of a transmission linkage as illustrated in FIG.2. The end of horizontal control lever 7 inside the housing 1 ispivotably supported on a fixed pin 11 and at the same time the lever 7is movable in its longitudinal direction in an oblong slot 12. The pivotpin 11 is located at the rear part of the base plate of housing 1 sothat the whole transmission linkage of FIG. 2 is movable in a planewhich extends at right angles to the plane of movement of the filmcapsule 5. The transmission mechanism of FIG. 2 further indicates anequalizing elbow lever 13 having two arms 15 and 16. The apex of theelbow lever 13 is pivotably supported on a fixed pivot axle 14projecting from the base plate of housing 1.

The end of arm 15 of elbow lever 14 is linked by a hinge joint 17 to thecontrol lever 7, whereas the end of the other arm 16 is linked to atransmission lever 19 by means of a hinge joint 18. The transmissionlever 19 extends substantially at right angles to the control lever 7and is supported at the end thereof remote from the film holder, on afixed pivot pin 20. Similarly as in the control lever 7, pivot pin 20guides the transmission lever 19 in an oblong slot 21 extending in thelongitudinal direction in the lever 19. Similar guiding slot 22 isprovided in the other end portion of the transmission lever and engagesin a pin 23 formed on an elongated slide carriage 25 which together witha transverse carriage constitute the film holder 24 for supporting thefilm capsule 5.

The film holder 24 is illustrated in detail in FIG. 3. The elongatedslide carriage 25 is movable on two parallel tracks 26 and 27. Toothedracks 28 and 29 are secured laterally to respective tracks 26 and 27 andare in engagement with pinions 31 and 32 of a driving shaft 30illustrated by dashed lines in FIG. 3. The driving shaft 30 is supportedfor rotation on the longitudinal slide carriage 25. One end of thelongitudinal slide carriage 25 is provided with the aforementioned pivotpin 23 engaging the oblong slot 22 of transmission lever 19 asillustrated in FIG. 2.

A transverse carriage 33 is supported on drive shaft 30 for movementtransverse to the movement of the longitudinal carriage 25. Thetransverse carriage 33 carries the film capsule 5. The transversecarriage 33 has a projecting pin 34 passing through an elongated guidingslot 35 formed in the longitudinal carriage 25. The central wires 36 and37 of two Bowden cables 39 and 38 are secured to the guiding pin 34 ofthe transverse carriage 33 for driving the latter in the transversedirection as it will be explained below in connection with FIG. 4. Thecables 39 and 38 are secured to the carriage 25 in a manner shown inFIG. 6.

FIG. 4 illustrates the transmission mechanism pertaining to the othercontrol lever 9 assigned in the given example for positioning the filmalong a vertical coordinate axis. The vertical control lever issupported for a pivotal movement in a plane perpendicular to themovement of the lever 7 and similarly as the latter is supported on afixed pivot pin 40 which engages an oblong slot 41 so that the verticalcontrol lever 9 can perform, apart from its rotary movement, atranslational movement in its longitudinal direction. An equalizingone-arm lever 42 is at one end thereof supported for pivotal movementabout a fixed pivot pin 43 projecting from a wall of the housing 1. Theother end of the lever 42 is hinged to the control lever 9 by means of ahinge joint 44. To equalize the movement of the projecting end of thelever 9 the fixed pivot pin 43 is located closer to the screen than thehinge joint 44.

The other ends of central wires 36 and 37 of Bowden cables 38 and 39 areattached to the vertical control lever 9 by means of attachment screw 45which is located between the free end of the lever 9 and the hinge joint44 of the equalizing lever. The length of the equalizing lever 42 andthe positions of its pivot points 43 and 44 as well as the position ofthe fixed pivot pin of the lever 9 are so designed that during the fullswing of the vertical control lever 9 the attachment screw 45 movesalong a substantially straight line.

The operation of the transmission device in the film reader of thisinvention will be explained first with reference to FIG. 2 illustratingthe displacement of the film holder along one of the coordinate axes bymoving the longitudinally slide carriage 25 along the guiding tracks 26and 27. FIG. 2 shows the film holder 24 in one end position close to thescreen 2 and the control lever 7 is in its extreme left hand position.Accordingly, the control lever 7 is movable to the right or pivotedcounterclockwise whereby the film holder 24 moves rearwardly along thetracks 26 and 27. The equalizing lever 13 during the movement of controllever 7 is pivoted clockwise about its fixed pivot axis 14 and rotatesthe transmission lever 19 about its fixed pivot pin counterclockwisewhereby the latter moves the film holder 24 in the aforementionedrearward direction. It will be noted that by moving the control lever 7the latter is first displaced rearwardly in the pin slot guide 11 and 12and remains in this position approximately up to the middle point of itshorizontal sweep whereupon it is again displaced in its longitudinaldirection to its original position. As a result of the combined pivotaland rectilinear movements of the control lever 7, the projecting end ofthe latter extends from the front frame 3 always about the same distanceduring the whole sweep of the latter.

A corresponding back-and-forth movement of the transmission lever 19relative to the fixed pivot pin 20 takes place during the movement ofthe control lever 7. As seen from FIG. 3, the transmission lever 19 isunilaterally attached to the longitudinal slide carriage 25 of the filmholder 24. In spite of this unilateral power transmission no canting ofthe carriage 25 takes place because the driving shaft 30 positivelytransmits each displacement of the longitudinal carriage 25 from onetoothed rack 28 to the other toothed rack 29 and thus simultaneouslymoves the carriage along the guiding tracks 26 and 27.

The transverse carriage 33 is driven on the longitudinal carriage 25 bymeans of the transmission mechanism assigned to control lever 9 asillustrated in FIG. 4. If the control lever 9 is rotatedcounterclockwise that means in the right-hand direction from theposition as illustrated in the Figure, it pulls via the central wire 37of Bowden cable 39 the transverse carriage 33 to the left (FIG. 3). Ifthe movement of the control lever 9 is reversed, the central wire 37 ofBowden cable 39 displaces the transverse carriage 33 in the longitudinalslot 35 to the right. The whole assembly of the transmission mechanismof this invention is illustrated in FIG. 5. It can be seen that theswinging movement of the vertical control lever 9 is transmitted viaBowden cables 38 and 39 to a non-illustrated transverse slide carriagewhereas the sweep of the horizontal control lever 7 is transmitted tothe non-illustrated slide carriage by the transmission lever 19.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in aspecific example of the film reader, it is not intended to be limited tothe details shown, since various modifications and structural changesmay be made without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:
 1. A film reader including a housingdefining a front wall, a rectangular screen arranged in the front wall,a projector having an illumination plane enclosed in said housing, and afilm holder accessible through said front wall and being guided in saidillumination plane, comprising two control levers movably arranged insaid housing and each having a free end portion extending through saidfront wall, one of said levers being movable alone one edge of saidscreen and the other lever along a transverse edge of said screen;reversing transmission means linked between said levers and said filmholder to move the same at a reduced speed in said illumination plane indirection opposite to the directions of movement of said levers wherebythe directions of movement of the film image projected on said screencorrespond to those of said levers, said film holder including alongitudinal carriage movable in one direction and a transverse carriagesupported on said longitudinal carriage for movement transverse to thatof the latter and being adapted for supporting a film to be projected;one of said control levers being rotatable about a fixed pivot point andat the same time guided for longitudinal displacement relative to saidfixed pivot point; an equalizing lever hinged to said one control leverand being pivotable about another fixed pivot point; said one controllever being movable in a plane transverse to said illumination plane;said equalization lever being an elbow lever the apex of which ispivotable about said fixed pivot pin; one of the arms of said elbowlever being hinged to said one control lever; said transmission meansincluding a transmission lever extending across said one control leverand being pivotable at one end thereof about a fixed pivot pin and beinglinked at the other end thereof to a pivot pin on said longitudinalcarriage of said film holder; the end portions of said transmissionlever including oblong slots engaging respective pivot pins to permitthe displacement of said transmission lever along its longitudinal axis;and the other arm of said equalizing elbow lever being hinged to saidtransmission lever.
 2. A film reader including a housing defining afront wall, a rectangular screen arranged in the front wall, a projectorhaving an illumination plane enclosed in the housing, and a film holderaccessible through said front wall and being guided in said illuminationplane, comprising two control levers movably arranged in said housingand each having a free end portion extending through said front wall,one of said levers being movable along one edge of said screen and theother lever along a transverse edge of said screen; and reversingtransmission means linked between said levers and said film holder tomove the same at a reduced speed in said illumination plane indirections opposite to the directions of movement of said levers wherebythe directions of movement of the film image projected on said screencorrespond to those of said levers; said film holder including alongitudinal carriage movable in one direction and a transverse carriagesupported on said longitudinal carriage for moveqent transverse to thatof the latter and being adapted for supporting a film to be projected;said transmission means including a pair of guiding tracks forsupporting said longitudinal carriage for movement in the direction ofone of said axes; a pair of toothed racks assigned to respective guidingtracks; a driving shaft supported for rotation on said longitudinalcarriage and having at each end thereof a driving pinion in mesh withsaid racks; said transmission lever being coupled to said longitudinalcarriage in the proximity of one of said racks; said vertical controllever being movable in a guiding slot arranged parallel to the plane ofmovement of said longitudinal carriage; said transmission means furtherincluding a second equalizing lever pivotable in said parallel planeabout a fixed pivot point and being hinged to said vertical controllever; a closed loop Bowden cable having its central wire attached atone point to said vertical control lever and at another point to saidtransverse carriage; the length of said second equalizing lever, theposition of said one attachment point of said Bowden cable wire relativeto the fixed pivot point and the guiding slot of said vertical controllever being designed such as to guide said Bowden cable wiresubstantially on a straight line during the movement of said verticalcontrol lever.